Problem: ${ 1.81 \times 9 = {?}} $
Solution: ${1}$ ${8}$ ${1}$ ${9}$ ${\times}$ ${.}$ ${0.01}\times {9}= {0.09}$ ${9}$ ${0.8}\times {9}= {7.2}$ ${2}$ ${1}\times {9}+{7}= {16}$ ${6}$ ${1}$ $\text{The top number has 2 digits to the right of the decimal.}$ $\text{The bottom number has 0 digits to the right of the decimal.}$ $\text{The product has 2 + 0 = 2 digits to the right of the decimal.}$ ${.}$ ${ 1.81 \times 9 = 16.29} $